Queensland's larger businesses are being encouraged to scale back electricity use again as the fallout from a major power plant fire continues.
The Australian Energy Market Operator has forecast a second "lack of reserve" notice in 24 hours, following the fire at the Callide C power station in central Queensland on Tuesday afternoon.
The fire knocked out about 3100 megawatts or 10 per cent of the state's power capacity, affecting about 477,000 customers.
Power was restored to most customers within two hours, but the impacts lingered on Wednesday.
AEMO is expecting loss of reserve 1 (LOR1) conditions from 5.30pm until 7pm on Wednesday.
"LOR1 market notice signals a reduction in pre-determined electricity reserve levels, encouraging generators to offer more supply, or large industrial or commercial consumers to reduce their demand," AEMO said in a statement.
Energy Minister Mick de Brenni said the fire was unprecedented, and it was lucky none of the plant's 226 workers were injured.
Earlier on Thursday, he said he was confident Queenslanders wouldn't experience more outages linked to the accident.
"Actions taken last night will ensure electricity supply continues to exceed demand and the Australian Energy Market Operator has forecast sufficient supply going forward," Mr de Brenni told parliament.
"We will have to continue to monitor the situation closely and update Queenslanders of any changes.
"This incident shows that unforeseen events can happen anywhere, and can have a cascading effect across the electricity system."
AEMO already issued a "lack of reserve" notice to the national market to import power to Queensland on Tuesday night.
Later, it was telling households to avoid using heavy appliances to "minimise stress on the system" until at least 9.30pm to mitigate the risk of further blackouts or brownouts.
Queensland was buying electricity from NSW on Wednesday morning for dispatch prices as high as $14,000 per megawatt hour.
Mr de Brenni said prices would fall and the state would return to exporting electricity to southern states as renewable solar and wind generation came online during the day.
However, AEMO is forecasting prices to surge to almost $15,000 per MWh between 5.30pm until 7pm on Wednesday.
The regulator is investigating the cause of the blaze and subsequent explosion in one of four turbines.
Built in 2001, the Callide C plant is one of the newest electricity generators in the state.
Federal Resources Minister Keith Pitt said coal-fired power had been "absolutely reliable for decades", but risk increases as assets come to the end of their lives.
"It's the same as your car... As your car gets older, well it has some more challenges if you don't keep the maintenance up to it," he told Sky News.
State Opposition Leader David Crisafulli said the balance sheets indicate the plant was being run for profit.
"They're not to be used as a cash cow, and I look at the returns of those generators and I have every reason to ask about maintenance, and I have every reason to ask about the operation, on the basis of that," he told reporters.
CS Energy executives met workers on Wednesday morning to discuss the situation, including the time frame for repairing the plant.
The Construction, Forestry, Maritime, Mining and Energy Union warned it could take months or even years to repair.